So, all u have to do is just think of a 10 digit number made from the numbers 0-9
My number is, 6537491082.

Prefix- First number

0. Cloud/Sea (Choose either one)

1. Leaf/Sun (Choose either one)

2. Sky/Flame (Choose either one)

3. Bird/Mottle (Choose either one)

4. Tiger/Dapple (Choose either one)

5. Branch/Rose (Choose either one)

6. Bush/Lily (Choose either one)

7. Night/Finch (Choose either one)

8. Robin/Mist (Choose either one)

9. Rain/Wolf (Choose either one)

Suffix- 2nd number

0. Wave

1. Shine

2. Splash

3. Berry

4. Thorn

5. Flight

6. Feather

7. Glow

8. Petal

9. Pounce

Color- 3rd number

0. Dark Grey
1. Golden
2. Blue/Grey
3. Reddish Brown
4. White
5. Brown
6. Light Brown
7. Light Grey
8. Orange
9. Black

Markings- 4th number

0. Mittens
1. Tabby
2. Classic Tabby
3. Spotted
4. Socks
5. Patches
6. Tail
7. Patch on chest
8. Points
9. Patches on muzzle, belly, and paws.

Marking Color- 5th number

0. White
1. Darker than base fur color
2. Lighter than base fur color
3. Black
4. Cream
5. White
6. Darker than base fur color
7. White
8. White
9. Lighter than base fur color

Fur texture- 6th number

0. Wavy
1. Curly
2. Very Soft
3. Long
4. Medium
5. Short
6. Sleek
7. Long with ear tufts
8. Short and shiny
9. Spiky with with ear tufts

Eye Color- 7th number

0. Blue
1. Yellow
2. Copper
3. Yellow-Green
4. Pale Blue
5. Green
6. Aqua
7. Minty Green
8. Dark green
9. Orange

Group- 8th number

0. RiverClan
1. SkyClan 
2. WindClan
3. RiverClan
4. SkyClan
5. ThunderClan
6. ShadowClan
7. Loner (just use your prefix)
8. Rouge (just use your prefix)
9. Kittypet (just use your prefix)

Rank- 9th number (If not clan then u can skip this)

0. Mediator
1. Warrior
2. Medicine Cat
3. Leader (change your suffix to star)
4. Elder
5. Deputy
6. Kit (change your suffix to kit)
7. Tunnler (Only if in WindClan; if not then regular warrior)
8. Warrior
9. Apprentice (change your suffix to paw)

Other- 10th number

0. Bob-tail
1. Scar on shoulder
2. Torn ear
3. Nicked ear
4. Normal
5. Normal
6. Half tail
7. Normal
8. Normal
9. Scar on muzzle

That all! (U can choose the gender of ur cat) :3  Please tell me what u got in the comments!

So, I got Bushflight, a Red-Brown cat with a cream patch on his chest, a torn ear, spiky fur with a tuft on his not torn ear, and yellow eyes. He is a Riverclan warrior.